Apparatus for installation and removal of threaded fittings



J. P. GOULD Filed Nov. 26, 1958 INVENTOR. gay]? 6 0 211d,

APPARATUS FOR INSTALLATION AND REMOVAL OF THREADED FITTINGS gss Dec. 18, 1962 3,fifi8,559 Patented Dec. 18, 1962 3,068,559 APPARATUS Emil ENSEALLATKON AND REMOVAL (H FETTINGS Jay P. Gould, 2311 Cont-airy Qlub Vista, Glcndora, Cal-.if. Filed Nov. 26, 1953, Ser. No. 776,562 2 tiiain'is. (Cl. 29213) This invention relates to apparatus for installation and removal of threaded fittings and more specifically to improvements in a tool for installation and removal of threaded pressure vessel fittings under pressure.

In my United States Patents Nos. 2,752,228 and 2,804,- 279, I have shown and described certain fittings for use in pressure vessels, such as in well heads for oil wells. These fittings, and the like, can be installed in and removed from such pressure vessels while under pressures in the order of several thousand pounds per square inch by means of a special tool that is the subject matter of my United States Patent No. 2,744,310. The tool shown in said patent is a pressure confining tool that is connected with a valve positioned over the fitting location and prevents observation of the fitting during installation and removal. Thus, installation and removal of such fittings under pressure are in the nature of blind operations. Since the fittings and tool for effecting these operations are described in detail in the above-mentioned patents, these structures will be discussed only enough for an understanding of the present invention.

It is the general object of the present invention to provide an improvement in a tool of the foregoing character.

Another object of the invention is to improve the portion or" the tool that engages the fitting so that the tool and fitting are easily aligned and positively connected together and held aligned with one another during installation and removal of the fitting under pressure.

Still another object of the invention is to improve the portion of such tool that engages the fitting so that the tool positively holds the fitting during installation and removal, yet is easily disengaged therefrom after installation or removal has been accomplished.

A further object of the invention is to improve that portion of such tool that engages the fitting so that the tool is easily and positively connected to the fitting, and at the same time is adapted to by-pass fluid pressure to equalize the pressure on opposite sides of the fitting to facilitate removal thereof.

Other objects and advantages or" the invention will be apparent from the following description taken in conjunction with the accompanying drawing, wherein:

FIG. 1 is an elevational view on a reduced scale and partially in section, showing the portion of a tool enibodying the present invention mounted for effecting removal of a threaded fitting from a vessel;

FIG. 2 is a longitudinal sectional view of the portion of the tool shown in PEG. 1 in one position of engagement with a fitting;

FIG. 3 is a view similar to EEG. 2 showing the portion of the tool in another position of engagement with the fitting;

FIG. 4 is a cross-sectional view taken along line 44 in FIG. 2;

FlG. 5 is a cross-sectional view taken along line 5-5 in FIG. 2;

FIG. 6 is a view similar to FIG. 2 showing a modified form of the invention; and

FIG. 7 is a cross-sectional view taken along line 7-7 in FIG. 6.

Generally speaking, the objects of the present invention are accomplished by providing a tool with a novel assembly comprising a wrench structure, and pilot means that leads the wrench structure into aligned engagement with the fitting preparatory to removal of the fitting. The pilot means is adapted to be positively connected to the fitting and the wrench structure is adapted to engage the fitting for rotating the fitting to effect its installation and removal. The wrench structure and the pilot means are relatively movable and resilient means is provided for urging the pilot means to an extended position so that it engages and is connectable with the fitting prior to engagement of the fitting by the wrench structure. Also, the pilot means is provided with a fluid passage that cooperates with a passage in the fitting to by-pass fiuid pressure during removal of the fitting, whereby pressure is substantially equalized on both sides of the fitting to prevent blow-out of the fitting during its removal.

in the drawing, FIG. 1 shows, by way of example, one form of fitting that may be installed and removed by tools embodying the present invention. The fitting, indicated generally at 11, is of the type shown in my aforementioned Patent No. 2,804,279, the fitting being a re movable plug for access to the interior of the pressure vessel, such as the production tubing of an oil well. Briefly, the fitting 11 comprises a cylindrical body portion having a tapered seat 12 near its inner end and is provided with threads 13 at its outer end. The fitting 11 is also provided with a head portion 14 on its outer end, the head portion, in this instance, having a hexagon shape for engagement by a socket wrench, or the like. The fitting 11 is mounted in a tubular nipple 16 that is internally threaded at its outer end for cooperation of the threads 13 on the fitting, and has a tapered seat 17 for cooperation with the seat 12 on the fitting to provide a seal against fluid flow therebetween. In FIG. 1 the fitting 11 is shown with its seat 12 in sealing engagement with the seat 17. The fitting 11 is also provided with an internal passage (not shown) that is opened when the seat 12 is raised from the seat 17. The passage in the fitting 11 includes an axial bore 18 in the head portion 14 (see FIGS. 2 and 3). The bore 13 is conventionally provided with internal threads, such as 2%. The pasv sage with the bore 18 thus provides flow communication from the interior ofvthe nipple 16 to the outside when the seat 12 is raised from the seat 17.

It will be understood that the fitting 11 can be installed and removed from the nipple 16 even under pressure by a tool such as that shown and described in my Patent No. 2,744,310. FIG. 1 shows a portion of such tool mounted for removal of the fitting 11 from the nipple 16 under pressure, the tool being indicated generally at 19 and the portion shown embodying the features of the present invention.

In use, the tool 19 and the nipple 16 are interconnected by a gate valve 21 having a passage 22 extending therethrough. The passage 22 is opened and closed by a valve member 23. The valve 21 is threadedly connected to the nipple 16 so that the passage 22 is substantially axially aligned with the fitting 11. The tool 19 includes a pressure confining tubular housing, a portion of which is shown at 24, that is threadedly connected with the passage 22 opposite the fitting 11 and in general axial alignment therewith. It will be understood that the threaded connections between the valve 21 and the nipple 16, and between the valve 21 and the housing 24 are sealed against pressure flow therethrough.

The tool 19 includes an elongated rod, fragmentarily shown at 26, which is axially disposed in the housing 24, and which is axially rotatable and reciprocable relative to the housing 24 by manipulating means (not shown) located outside the housing 24. The structure of this portion of the tool is completely shown and described in my aforesaid patent. The inner end of the rod 26 is provided with an assembly adapted to engage the head portion 14 of the fitting 11 for rotating the same to effect installation or removal of the fitting. This assembly is indicated generally at 27 and embodies the features of the present invention. The assembly 27 constitutes an extension on the rod 26 and is provided with wrench structure for engagement with the head portion 14 of the fitting so that the fitting may be rotated relative to the nipple 16. A clearance 28 beween the assembly 27 and the inner wall of the housing 24 is provided to conduct pressure fluid to an equalizing means in the tool to balance the pressure on the rod 26 so that it may be reciprocated freely, as described in said patent.

FIGS. 2 and 3, illustrating a preferred form of the assembly 27, comprises an elongated member 29 that is removably and adjustably mounted in coaxial fixed relation on the end of the rod 26. In this instance the member 29 is tubular, having an axial bore 31 and-a plurality of radial holes 30. At one end the member 29 is counterbored as at 32, the counterbored portion being telescoped over the end of the rod 26 and secured thereto by a cap screw 35 that projects outwardly into any one of the holes 30.

At its opposite end, the member 29 is provided with wrench structure adapted to engage the head portion 14 of the fitting 11. Inasmuch as the head portion 14 is, in this instance, shaped in the form of a hexagon nut, the wrench structure is a socket Wrench element 33 and is rigidly fixed to the end of the member 29. As shown in FIG. 5, one end of the element 33 is a l2-pointed type socket 34 which may be engaged with the hexagon head 14 with a minimum of angular movement. The opposite end of the element 33 is bored to provide an annular seat 25. The end of the member 29 is telescoped into the bore 36 and abuts the seat 25. After assembly in this fashion, the socket wrench element 33 and the elongated member 26 are Welded together, as shown at 33a in FIGS. 2 and 3.

It is apparent that the wrench element 33 will be somewhat remote from the operator during installation and removal of the fitting, and that installation or removal must be accomplished without sight of the wrench element or of the fitting. Under these circumstances misalignment between the wrench structure and the head portion 14 would hamper engagement with the fitting when removal is attempted. To avoid this difficulty the assembly 27 is provided with a pilot element 36, that is adapted to coact with the fitting, as the assembly is moved toward the fitting, to align the Wrench structure with the head portion of the fitting. The pilot element 36 is also adapted to be positively, but releasably, connected to the fitting so that the fitting cannot be inadvertently dropped or released, the fitting being held in rigid axial alignment with the rod 26 by the pilot element 36 as removal or installation thereof is accomplished.

In the present instance, the pilot element 36 is a generally cylindrical member and has an inner end portion 37 projecting into the bore 31 so that the element 36 is held coaxial with the member 29 and the socket wrench element 33. The diameter of the end portion 37 is approximately the same as the diameter of the bore 31. The outer end of the pilot element 36 is bevelled as at 38 in order to readily enter the axial bore 18 in the fitting 11 and to cam the pilot element, and hence the wrench structure 33, into axial alignment with the bore 18 as the pilot element 36 is moved into the fitting. Adjacent the surface 38 the pilot element 36 is provided with external threads 39 adapted to engage the threads 20 in the bore 18 so that the pilot element can be connected to the fitting 11 upon rotation of the element 36 relative to the fitting. The pilot element 36 is also provided with an annular shoulder 40 adjacent the inner end of the threads 39 as seen in FIGS. 2 and 3 to act as a stop to limit insertion of the pilot element into the bore 18 of the fitting. Connection of the element 36 to the fitting by the threads 39 provides a positive engagement with the fitting which can be easily established or released, but which avoids the possibility of inadvertent release of the fitting during the removal thereof.

it is important that the pilot element 36 be engaged with and securely connected to the fitting 11 prior to engagement by the so: (6t wrench element 33. To this end, the pilot element 36 is mounted in axially movable relation to the elongated member 29 and the socket wrench element 33, the pilot element being movable between an extended and a retracted position. FIG. 2 shows the element 36 in its extended position after having been threadedly connected to the fitting 11 and FIG. 3 shows the element 36 in its retracted position, after the socket Wrench element 33 has been moved into engagement with the head portion 14. The pilot element 36 normally occupies the extended position and means is provided for resiliently urging the pilot element 36 toward such extended position. In the embodiment of the invention shown in FIGS. 2 and 3 the urging means comprises piston and cylinder structure which utilizes the force provided by compressed gas for urging the element 36 to its extended position. In this form of the assembly, the socket wrench element 33 and the adjacent end of the elongated member 29 are counterbored, as at ii, to provide an annular shoulder 42. The pilot element 36 has a cylindrical portion 43 of reduced diameter commencing at a point approximately opposite the shoulder 42, when the pilot element is in its extended position, and extending axially toward the outer end to a shoulder or annular surface 44. The annular surface 44 extends radially outwardly and faces the shoulder 42 on the elongated member 29. From the surface 44 toward its outer end, the member 36 is enlarged, having a diameter substantially equal to the diameter of the counterbore 41. Thus, the annular surface 44 corresponds to the head end of a piston and the annular shoulder 42 corre sponds to a cylinder head. The pilot element 36 is also provided with O-ring grooves 46 and 47 on opposite sides of the portion 43 in which are mounted O-rings 48 and 49, respectively, to form a fluid-tight seal between the pilot element 36 on the one hand, and the elongated member 29 and the socket wrench element 33 on the other hand, thereby preventing fiuid leakage from the compression chamber 50 defined therebetween. In order to introduce a fluid into the compression chamber 50, the elongated member 29 is provided with a hole 51 through the wall thereof into the compression chamber 50. The hole 51 is closed by a removable plug 52 threaded and sealed therein. Thus, when the pilot ele ment 36 is forced into its retracted position for engagement of the socket wrench element 33 with the fitting, the volume of the compression chamber 50 is greatly reduced and the gas contained therein is compressed. The compressed gas, of course, exerts a force on the annular surface 44 of the pilot member for urging the pilot element 36 back to its extended position.

Since rotative force must be transferred from rod 26 to tl e pilot element 36 in order to effect the threaded connection between the pilot element and the threads 20 in the fitting 11, the pilot element 36 is mounted in rotatably fixed position relative to the elongated member 29. Also, the element 36 is axially movable relative to the elongated member 29 between the extended and retracted positions, as previously mentioned. To provide this relationship, the end portion 37 of the pilot element 36 is provided with a transverse longitudinally extending slot 53. A transversely extending crosspin 54 is rigidly mounted in the elongated member 29 and projects through the slot 53. Thus, the pin 54 limits longitudinal movement of the pilot element 36 and also transfers rotational force from the elongated member 29 and, hence, the rod 26, to the pilot element 36.

The assembly 27 also includes a passage for by-passing fluid pressure from the fitting 11 to the space 28 between the housing 24 and the assembly 27. In the present instance the pilot element 36 has an axial bore 56 that extends from the lower end of the pilot member 36 into the slot 53. A second bore 57 interconnects the slot 53 and the bore 31 in the elongated member 29. Clearance is provided between the rod 26 and the elongated member 29, and therefore fluid is free to pass through such clearance and out the holes 36 in the elongated member 29 to the clearance 28. Thus, when the pilot element 36 is connected to the fitting 11, the bore 56 opens into the bore 18 in the fitting. As the seat 12 is disengaged from the seat 17 due to rotation of the fitting, the pressure fluid below the lower end of the fitting 11 is by-passed to the upper end of the fitting 11, through the bore 18, the bore 56, the slot 53, the bore 57, the clearance between the rod 26 and the member 29, the holes 30, and the clearance 28, and pressure is equalized on opposite sides of the fitting 11 to facilitate removal of the fitting.

In using the tool 19 to remove a fitting from a pressure vessel, the valve 21 and the tool are assembled on the nipple 16 as shown in FIG. 1, and the valve 21 is opened. The rod 26, together with the structure 27, is moved toward the fitting 11 through the passage 22 in the valve. During such movement, the pilot element 36 will occupy its extended position relative to the elongated member 29, because of the resilient action provided by the compression chamber 51 In the event the pilot element 36 is slightly misaligned with respect to the fitting 11, the bevel 38 will coact with the head portion 14 of the fitting and, by cam action, align the pilot element 36 with the fitting 11. The rod 26 is then rotated to engage the threads 39 on the pilot element with the threads in the fitting 11. After connection of the pilot element with the fitting is completed, the rod 26 is forced axially toward the fitting so that the pilot element 26 occupies its retracted position, as shown in FIG. 3, and the gas in the pressure chamber is compressed. This brings the socket wrench element 33 into engagement with the head portion 14 of the fitting. To effect complete engagement of the socket wrench element 33 it may be necessary to rotate the rod 26 slightly during such axial movement. Thereafter, the rod 26 is rotated to unscrew the fitting 11 from the nipple 16. During rotation, the seat 12 on the fitting 11 is disengaged from the seat 17, thus opening the passage to by-pass pressure fluid to the upper end of the fitting 11. Thereafter, rotation of the fitting is continued until the threads 13 of the fitting 11 are disengaged from the nipple 16. The assembly 27 together with the fitting 11 is then withdrawn into the housing 24 and the valve 21 closed. The tool 19 can then be detached from the valve 21 and the fitting removed from the pilot element 36.

To install the fitting, the process is substantially reversed. The fitting 11 is first threadedly connected to the pilot element 36 and the assembly 27 and the fitting is then withdrawn into the housing 24. The tool 19 is connected to the valve 21 as shown in FIG. 1 and the valve opened. Upon opening of the valve, pressure from the nipple 16 passes into the clearance 28, equalizing the pressure in the tool and around the fitting 11. The assembly 27 together with fitting 11 is then moved by the rod 26 through the passage 22 in the valve and into the nipple 16. The member 26- is then forced inwardly to engage the socket wrench element 33 with the head 14 and rotated to engage the threads 13 of the fitting 11 with the nipple 16. Rotation is continued until the seat 12 on the fitting is seated against the corresponding seat 17 in the nipple 16. When this occurs the passage through the fitting is closed and the tool 19 can be disengaged from the fitting 11. This is accomplished by releasing the axial force on the rod 26 so that the socket wrench element 33 disengages the head portion 14 of the fitting as a consequence of the force exerted by the compressed gas in the chamber 50. The rod 26 is then rotated to disconnect the threads 39 on the pilot element 36 from the threads 20 on the fitting, so that the assembly 27 may be withdrawn into the housing 24. Thereafter the tool 19 and the valve 21 may be disassembled from the nipple 16.

FIGS. 6 and 7 show a second, somewhat simplified, form of the assembly 27. This second form of the assembly includes an elongated member 66 which has an axial bore 67 extending into the upper end thereof to receive the rod 26, and has radial holes 68 opening into the bore 67 to selectively receive a cap screw, similar to the screw 35, shown in FIGS. 2 and 3. The member 66 has another axial bore 69 extending into its lower end and a counterbore 71 of larger diameter than the bore 69. it should be noted that in this instance the bore 66 and the bore 69 are separated by an imperforate wall 72'.

A socket wrench element 73, similar to the element 33, is rigidly secured to the lower end of the elongated member 66. The socket wrench element 73 is generally tubular, having an intern-a1 diameter at one end approximately equal to the external diameter of the elongated member 66 in order that the end of the elongated member may be inserted therein. The opposite end of the socket wrench element is formed as a conventional l2- pointed wrench socket 74, as shown in FIG. 7, for engagement with a hexagon head, such as 14 on the fitting 11. Intermediate its ends, the socket element 73 is provided with an internal radial flange portion 76, the inner diameter of which is slightly greater than the diameter of the bore 71 in the member 66. The flange 76 provides an annular seat 7'7 against which the lower end of the elongated member 66 abuts. Upon assembly, the socket wrench element 73 and the elongated member 66 are welded together, as shown in FIG. 6.

This form of the assembly also includes a generally cylindrical pilot element 78 mounted in coaxial relation with respect to the socket wrench element 73 for movement between an extended and retracted position. The upper end of the pilot element projects into the bore 71 and is substantially the same diameter as the bore 71. The lower end of the pilot element 78 is substantially identical to the corresponding end of the pilot element 36, having a bevelled surface 79, threads 8-1 and an annular shoulder 82. Likewise, the pilot element 78 has a transverse axially extending slot 83 intermediate its ends and a fluid by-pass passage 84 extending from the lower end into the slot 83. The pilot element 78 is, however, considerably shorter than the pilot element 36 and a transversely extending crosspin 86 is mounted in holes 87 through flange portion '76 of the socket wrench element and projects through the slot 83- for limiting movement of the pilot element.

In this form of the assembly, the pilot element 78 is resiliently urged toward its extended position by spring means. Thus, a coil compression spring 83 is mounted between the pilot element 78 and the elongated member 66, the spring having one end disposed in the bore 69, and bears against the Wall 72. The opposite end of the spring is disposed in a seat 87 formed in the pilot element 78. The pilot element 78 is therefore urged outwardly toward its extended position by the spring 38.

In the present assembly, pressure fluid is by-passed through the passage 84, the slot 83, a clearance 89 between the fiange 77 land the pilot element 78, and the space between the socket wrench portion 74- and the pilot element 78. It will be recognized that a tool equipped with this form of the assembly, however, will be operated in substantially the same fashion as a tool equipped with the first form, discussed above.

It is obvious from the foregoing that the second form of the assembly is considerably simpler than the form first described and for that reason is the preferred form of the invention for use in pressure vessels which do not contain substances that will attack stress-ridden seasons springs, such as hydrogen sulfide and the like. In many oil wells, however, the hydrogen sulfide content is high and frequent spring failure is experienced when the second form of the assembly is used. Consequently, the first form of the assembly, provided with the compression chamber urging means, is the preferred form for use in connection with oil wells and the like.

From the above it is seen that the present invention provides novel wrench assembly for tools which are used to install and remove threaded pressure vessel fittings under pressure. The assembly is adapted to be positively, yet releasably, connected to the fitting, and is adapted to hold the fitting in alignment with the tool during installation. The assembly is also self-aligning with an installed fitting so that it can be easily coupled to the fitting notwithstanding the fact that the coupling operation cannot be observed by an operator. Moreover, the assembly is provided with a passage for by-passing fluid pressure to equalize the pressure on opposite sides of the fitting.

Although the invention has been described in connec tion with certain specific embodiments, it is to be understood that various modifications and alternative structures may be resorted to without departing from the scope of the invention as defined in the appended claims.

I claim:

1. An assembly for operating and handling a fitting that is rotatably and releasably coupled to a base having a flow control valve thereon, said assembly comprising an operating rod operable through said valve and rotatable with respect to said fitting; an elongate member adapted to be connected at one end thereof to said operating rod in coaxial alignment therewith, said elongate member defining an axial bore extending from the opposite end thereof, said bore defining a' female wrench structure and said opposite end adapted to engage said fitting for rotation thereofupon rotation of said rod and elongate member; a pilot element mounted with-in said bore for sliding axial movement with respect thereto, said pilot element being rotatably fixed with respect to said elongate member and axially movable from an extended position to a retracted position. said pilot element having a tapered wall convergent toward the outer end thereof and a threaded portion axi lly inwardly of said tapered Wall, said male threads being engageable with a female threaded axial bore of said fitting, said pilot element at said extended position being adapted to guide said elongate member into axial alignment with said fitting and to engage said male threads thereof with said female threaded bore, said pilot ele ment at said restricted position being positioned within said bore whereby said wrench structure engages said fitting; said exterior wall of said pilot element and said interior Wall of said elongate member defining a differential piston and cylinder annulus therebetween, said interior wall of said elongate member defining a transverse cylinder shoulder of said annulus, said exterior wall of said pilot element defining an outer transverse piston shoulder of said annulus, a quantity of gas under compression contained within said annulus whereby the force of said gas exerts an outward force upon said pilot element to urge said pilot element to said extended position.

2. An assembly for operating and handling a fitting that is rotatably and releasably coupled to a base having a fio w controlling valve thereon, said assembly compris an operating rod operable through said valve and rotatable with respect to said fitting; an elongate member adapted to be connected at one end thereof to said operating rod in coaxial alignment therewith, said elongate member defining an axial bore extending from the opposite end thereof, said bore defining a female wrench structure at said opposite end adapted to engage said fitting for rotation thereof upon rotation of said rod and elongate member; a pilot element mounted within said bore for sliding axial movement with respect thereto, said pilot element being rotatably fixed with respect to said elongate member and axially movable from an extended position to a retracted position, said pilot element having a'tapered wall convergent toward the outer end thereof and a male threaded portion axially inwardly of said tapered wall, said male threads being engageable with a female threaded axial bore of said fitting, said pilot element at said extended position being adapted to guide said elongate member into axial alignment with said fitting and to engage said male threads thereof with said female threaded bore, said pilot element at said retracted position being positioned within said bore whereby said wrench structure engages said fitting; said elongate member and said pilot element having a longitudinally extending first equalizing fluid passage adapted to communicate with the passage said fitting, said elongate member defining a longitudinally extending second equalizing fluid passage in communication with said pilot element fluid passage, a third equalizing lluld passage between said elongate member and said operating rod communicating between said second equalizing fluid passage and the exterior of said elongate member for by-passing pressure fluid through said elongate member and said pilot element to equalize the pressure on opposite ends of said fitting to facilitate removal thereof; and means for normally urging said pilot element to said extended position.

References Cited in the file of this patent UNITED STATES PATENTS .HN... i 1 l 

